The present invention relates to a method of manufacturing an active matrix type liquid-crystal display device.
A liquid-crystal display device is thin and light and the power consumption thereof is low. By virtue of these features, it is widely used as a display device for notebook-type personal computers and word-processors and small-sized TVs. In particular, an active-matrix type liquid-crystal display device is promising for a large-sized TVs and the like, since it has a quick responsiveness and a high contrast and is capable of multi-gray-scale display.
The liquid-crystal display device comprises electrodes such as scan lines and switching elements such as thin-film transistors. The liquid-crystal display device is manufactured by repeating thin-film forming steps, PEP steps for forming photoresist masks, and etching steps for removing unnecessary portions of thin films.
In these years, with an increase in size of screens of the liquid-crystal display devices, a manufacturing apparatus matching with large screens is required. However, exposure of photoresist for a large screen can be performed by using a conventional small-sized exposure apparatus by dividedly exposing a plural divided regions of the screen.
In general, when a photoresist, etc. is dividedly exposed, there is a case where positional displacement at the time of exposure is visually recognized at the division lines or boundaries of the divided regions. To cope with this problem, the division lines are formed of turned-up regions or insular regions, thereby smoothing a variation gradient of characteristics at boundaries between the divided regions and making seams of divided regions less visible.
When a photoresist is dividedly exposed, intersections of horizontal division lines and vertical division lines are generally formed of straight line segments. If the width of regions of the horizontal division lines and vertical division lines is increased to make the boundaries of the divided regions less visible, the straight line segments at the intersections are elongated. Consequently, exposure displacement may be visually recognized at the straight line segments. More specifically, the boundaries become less visible if the division lines are formed of turned-up regions or insular regions and the width of engagement portions of adjacent divided regions is increased. In this case, however, at the intersections, the boundaries become straight line segments with no insular or turned-up regions, and these straight line segments may be recognized.